"Horseshoe Canyon, formerly known as Barrier Canyon, is in a remote area west of the Green River and north of the Canyonlands National Park Maze District in Utah, USA. It is known for its collection of Barrier Canyon Style (BCS) rock art, including both pictographs and petroglyphs, which was first recognized as a unique style here. A portion of Horseshoe Canyon containing The Great Gallery is part of a detached unit of Canyonlands National Park. The Horseshoe Canyon Unit was added to the park in 1971 in an attempt to preserve and protect the rock art found along much of its length.

Human presence in Horseshoe Canyon has been dated as far back as 7000-9000 B.C., when Paleo-Indians hunted large mammals such as Mastodons and Mammoths across the southwest. Later inhabitants included the Desert Archaic culture, the Fremont culture, and Ancestral Pueblo People. Occupation by the Fremont and Ancestral Puebloans was relatively brief; it is believed that the canyon was abandoned by Native American peoples by 1300 A.D.

The Great Gallery is one of largest and best preserved collections of Barrier Canyon Style rock art in the United States. The gallery was a product of the Desert Archaic culture, a nomadic group of hunter-gatherers predating the Fremont and Ancestral Puebloans. The panel itself measures about 200 feet (61 m) long and 15 feet (4.6 m) high. The panel contains about 20 life-sized anthropomorphic images, the largest of which measures over 7 feet (2.1 m) tall. Reproductions of the paintings are in the Museum of Modern Art in New York and the Denver Natural History Museum."

See: http://en.wikipedia.org/wiki/Horseshoe_Canyon_(Utah)